<?php
/*
 *  $Id: From.php 1080 2007-02-10 18:17:08Z romanb $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Query_Check
 *
 * @package     Doctrine
 * @subpackage  Query
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 1080 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Query_Check
{
	/**
	 * @var Doctrine_Table $table           Doctrine_Table object
	 */
	protected $table;

	/**
	 * @var string $sql                     database specific sql CHECK constraint definition
	 *                                      parsed from the given dql CHECK definition
	 */
	protected $sql;

	protected $_tokenizer;

	/**
	 * @param Doctrine_Table|string $table  Doctrine_Table object
	 */
	public function __construct($table)
	{
		if ( ! ($table instanceof Doctrine_Table)) {
			$table = Doctrine_Manager::getInstance()
			->getCurrentConnection()
			->getTable($table);
		}
		$this->table = $table;
		$this->_tokenizer = new Doctrine_Query_Tokenizer();
	}

	/**
	 * getTable
	 * returns the table object associated with this object
	 *
	 * @return Doctrine_Connection
	 */
	public function getTable()
	{
		return $this->table;
	}

	/**
	 * parse
	 *
	 * @param string $dql       DQL CHECK constraint definition
	 * @return string
	 */
	public function parse($dql)
	{
		$this->sql = $this->parseClause($dql);
	}

	/**
	 * parseClause
	 *
	 * @param string $alias     component alias
	 * @param string $field     the field name
	 * @param mixed $value      the value of the field
	 * @return void
	 */
	public function parseClause($dql)
	{
		$parts = $this->_tokenizer->sqlExplode($dql, ' AND ');

		if (count($parts) > 1) {
			$ret = array();
			foreach ($parts as $part) {
				$ret[] = $this->parseSingle($part);
			}

			$r = implode(' AND ', $ret);
		} else {
			$parts = $this->_tokenizer->quoteExplode($dql, ' OR ');
			if (count($parts) > 1) {
				$ret = array();
				foreach ($parts as $part) {
					$ret[] = $this->parseClause($part);
				}

				$r = implode(' OR ', $ret);
			} else {
				$ret = $this->parseSingle($dql);
				return $ret;
			}
		}
		return '(' . $r . ')';
	}

	public function parseSingle($part)
	{
		$e = explode(' ', $part);

		$e[0] = $this->parseFunction($e[0]);

		switch ($e[1]) {
			case '>':
			case '<':
			case '=':
			case '!=':
			case '<>':

				break;
			default:
				throw new Doctrine_Query_Exception('Unknown operator ' . $e[1]);
		}

		return implode(' ', $e);
	}

	public function parseFunction($dql)
	{
		if (($pos = strpos($dql, '(')) !== false) {
			$func  = substr($dql, 0, $pos);
			$value = substr($dql, ($pos + 1), -1);

			$expr  = $this->table->getConnection()->expression;

			if ( ! method_exists($expr, $func)) {
				throw new Doctrine_Query_Exception('Unknown function ' . $func);
			}

			$func  = $expr->$func($value);
		}
		return $func;
	}

	/**
	 * getSql
	 *
	 * returns database specific sql CHECK constraint definition
	 * parsed from the given dql CHECK definition
	 *
	 * @return string
	 */
	public function getSql()
	{
		return $this->sql;
	}
}